<head>
  <style> body { margin: 0; } </style>

  <script src="//unpkg.com/force-graph"></script>
  <!--<script src="../../dist/force-graph.js"></script>-->
</head>

<body>
  <div id="graph"></div>

  <script>
    const gData = {
      nodes: [...Array(9).keys()].map(i => ({ id: i })),
      links: [
        { source: 1, target: 4, curvature: 0 },
        { source: 1, target: 4, curvature: 0.5 },
        { source: 1, target: 4, curvature: -0.5 },
        { source: 5, target: 2, curvature: 0.3 },
        { source: 2, target: 5, curvature: 0.3 },
        { source: 0, target: 3, curvature: 0 },
        { source: 3, target: 3, curvature: 0.5 },
        { source: 0, target: 4, curvature: 0.2 },
        { source: 4, target: 5, curvature: 0.5 },
        { source: 5, target: 6, curvature: 0.7 },
        { source: 6, target: 7, curvature: 1 },
        { source: 7, target: 8, curvature: 2 },
        { source: 8, target: 0, curvature: 0.5 }
      ]
    };

    const Graph = new ForceGraph(document.getElementById('graph'))
        .linkDirectionalParticles(2)
        .linkCurvature('curvature')
        .graphData(gData);
  </script>
</body>